This seminal paper reports the first case of DNA transfer from a human bacterial pathogen, Bartonella henselae, to the host human cell. Furthermore, B. henselae becomes the second known bacterium, after Agrobacterium tumefaciens, that can transfer genetic material into eukaryotic cells.

Agrobacterium, that genetically transforms plants, has been considered to represent the only known naturally occurring case of trans-kingdom DNA transfer from bacteria to eukaryotes. This study broke this dogma, demonstrating that a human pathogen, B. henselae, is capable of genetically transforming its host cell. In fact, this discovery was not entirely unexpected as Agrobacterium can, under laboratory conditions, transform non-host organisms, such as fungi and animal cells, indicating that the mechanism for DNA transfer is evolutionarily conserved ”，来自华盛顿大学（University of Washington）的Gene Nester也评价道：“

This article is interesting because it demonstrates that the bacterial pathogen Bartonella henselae can transfer DNA into human cells by a type IV secretion system. This is the only known case of such DNA transfer into human cells, except for the transfer by the plant pathogen Agrobacterium under laboratory conditions.

The authors have presented convincing evidence that a cryptic plasmid in B. henselae can be transferred at a low frequency into a human endothelial cell line. Transfer is increased 100-fold if a secretion signal is fused to the C-terminus of the Mob protein of the plasmid. Various regions of the plasmid are shown to be integrated into the human chromosome, a process that appears to depend on cell division. The authors suggest that Bartonella might serve as a vector for gene delivery systems for DNA vaccinations and gene therapy”，足见此项研究具有十分重要的意义，并在构建相关基因工程载体和基因治疗方面提供了一项策略。PNAS全文详见附件，F1000上的链接http://f1000.com/12877956。